String NullErrorException

Discussion in 'Spigot Plugin Development' started by XxFroggyKnightxX, May 22, 2016.

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  1. XxFroggyKnightxX

    XxFroggyKnightxX

    Alright so just a straight forward rundown of my problem is that I'm using

    Code (Text):

    String map_name = plugin.getConfig().getString("Maps." + storage.current_map + ".name");
     
    for getting a name of the current map integer with a String. Now, where it confuses me is the fact it gives me a java.lang.NullPointerException if anyone knows why it's causing this, please do let me know. Thanks.
     
    #1 XxFroggyKnightxX, May 22, 2016
    Last edited: May 22, 2016
  3. Redrield

    Redrield

    plugin could be null storage.current_map could be null, the return value from getConfig() could be null. Do null checks
     
    #2 Redrield, May 22, 2016
    • Agree Agree x 1
  5. XxFroggyKnightxX

    XxFroggyKnightxX

    alrighty, thanks.
     
    #3 XxFroggyKnightxX, May 22, 2016
  7. Coltll

    Coltll

    I'm gonna assume you're sure that your string isn't empty.

    "plugin" is likely null.

    this. ignore me.
     
    #4 Coltll, May 22, 2016
  9. Choco

    Choco
    Moderator

    1. Code brackets are square brackets, and not diamond brackets ;)
    2. Your naming conventions are strange. Use lowerCamelCase
    3. Plugin could potentially be null

    EDIT: Damn I got sniped real hard there
     
    #5 Choco, May 22, 2016
  11. XxFroggyKnightxX

    XxFroggyKnightxX

    Since you guys have been saying "plugin" could be null. I'm using this
    Code (Text):
     
    public static me.xfrogx.Main plugin;

    public StartGame(me.xfrogx.Main m) {
        plugin = m;
    }
     
    for getting the main in plugin for the string.
     
    #6 XxFroggyKnightxX, May 22, 2016
  13. Redrield

    Redrield

    It's okay :3
     
    #7 Redrield, May 22, 2016
    • Friendly Friendly x 1
  15. Redrield

    Redrield

    Where do you define storage.current_map?
     
    #8 Redrield, May 22, 2016
    • Agree Agree x 1
  17. XxFroggyKnightxX

    XxFroggyKnightxX

    Inside of my storage class, where I made the public static ints.
     
    #9 XxFroggyKnightxX, May 22, 2016
  19. Redrield

    Redrield

    Can you show me the code where it's defined?
     
    #10 Redrield, May 22, 2016
  21. XxFroggyKnightxX

    XxFroggyKnightxX

    Hold up I think I got it. Testing it quick
     
    #11 XxFroggyKnightxX, May 22, 2016
  23. XxFroggyKnightxX

    XxFroggyKnightxX

    Code (Text):

    public class storage implements Listener{
        public static me.xfrogx.Main plugin;

        public storage(me.xfrogx.Main m) {
            plugin = m;
        }

        public static HashMap<Player, UUID> Blue = new HashMap<Player, UUID>();
        public static HashMap<Player, UUID> Red = new HashMap<Player, UUID>();
        public static HashMap<Player, UUID> Spec = new HashMap<Player, UUID>();

        public static String yes = "yes";
        public static String no = "no";

        public static int red_wool = 10;
        public static int blue_wool = 10;

        public static int current_map = 1;
        public static int next_map = 2;
        public static int prev_map = 0;

        public static int countdown = 30;

        public static HashMap<String, Boolean> lobby = new HashMap<String, Boolean>();
        public static HashMap<String, Boolean> starting = new HashMap<String, Boolean>();
        public static HashMap<String, Boolean> in_game = new HashMap<String, Boolean>();
        public static HashMap<String, Boolean> end_game = new HashMap<String, Boolean>();

        public static HashMap<String, Boolean> won = new HashMap<String, Boolean>();


    }
     
    that's the whole class storage.
     
    #12 XxFroggyKnightxX, May 22, 2016
  25. Redrield

    Redrield

    Can you give us the full error message?
     
    #13 Redrield, May 22, 2016
  27. XxFroggyKnightxX

    XxFroggyKnightxX

    Code (Text):

    at java.lang.Thread.run(Unknown Source) [?:1.8.0_77]
    Caused by: java.lang.NullPointerException
            at me.xfrogx.Game.StartGame.startGame(StartGame.java:43) ~[?:?]
            at me.xfrogx.Cmds.StartCMD.onCommand(StartCMD.java:33) ~[?:?]
            at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) ~[1.9.2.jar:git-Spigot-e6f93f4-d884ab3]
            ... 15 more

     
     
    #14 XxFroggyKnightxX, May 22, 2016
  29. Redrield

    Redrield

    Show us what's on line 43 of StartGame, and line 33 of StartCMD
     
    #15 Redrield, May 22, 2016
  31. XxFroggyKnightxX

    XxFroggyKnightxX

    StartCMD is just the void, StartGame. And line 43 is the Strings that're giving me the error.
     
    #16 XxFroggyKnightxX, May 22, 2016
  33. Redrield

    Redrield

    It says that the error is being caused at StartCMD line 33, as well as the line you already showed us. What is it?
     
    #17 Redrield, May 22, 2016
  35. XxFroggyKnightxX

    XxFroggyKnightxX

    Code (Text):

    if (cmd.getName().equalsIgnoreCase("start")) {
        if (p.hasPermission("server.owner")) {

          //  Start.StartGame(p); // called when command is ran \\
            Bukkit.broadcastMessage("TTT");
            StartGame.startGame();

        }
    }
     
    That's line 33 of the StartCMD.
     
    #18 XxFroggyKnightxX, May 22, 2016
  37. XxFroggyKnightxX

    XxFroggyKnightxX

    I think I might've found the error, not too sure. But could it possibly be the fact that I'm making a string using an integer?
     
    #19 XxFroggyKnightxX, May 22, 2016
  39. Redrield

    Redrield

    Hold on, is the method that string is in static? If it is then the problem is plugin.
     
    #20 Redrield, May 22, 2016
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